Method for solvent deasphalting of residual oil



May 21, 1957 H. G. CORNEIL ET AL 2,793,163

METHOD FOR SOLVENT DEASFHALTING OF RESIDUAL OIL Filed Oct. 15, 1954Propane Hawkins Residual Oil l4 Propane solution A "-0f cracking stockfree from metallic contaminants.

Residual charge containing metallic contaminants.

Asphalt containing metallic contaminants FIG. I.

Residual charge Hawkin's residual oil Propane FIG. 2.

INVENTORS.

Hampton 6. Cornell, BY Gilmore T- 6win,

Paul E Korbach,

METHOD FGR SQLVE'NT DEASPHALTING OF RESIDUAL OIL Hampton G. Corneil andGilmore T. Gwin, Baytown, Tex., and Paul F. Korbach, Shellield, Ala.,assignors, by mesne assignments, to Esso Research and EngineeringCompany, Elizabeth, N. J., a corporation of Delaware Application October15, 1954, Serial No. 462,440

7 Claims. (Cl. 196-1446) The present invention is directed to a methodof removing ash contaminants from residual petroleum fractions.

Substantially all of the crude petroleum oils commercially processedcontain substantial amounts of ash. An important part of this ashconsists of metallic contaminants of the type of nickel, vanadium andiron. The residual oils resulting from the disillation of such crudeoils contain such an amount of ash including such metal contaminants asto be undesirable feed stock for catalytic cracking operations. Thesecontaminants may be removed to a great extent by deasphalting, such aswith liquefied normally gaseous hydrocarbons. This invention is based onthe discovery that the overall removal of metal contaminants is greaterwhen a mixture of a low asphalt containing residum and residuum derivedfrom crude oil from the Hawkins field in Texas is deasphalted than whenthe two residua are deasphalted separately to the same total deasphaltedoil yield.

The present invention may briefly be described as contacting a residualpetroleum fraction containing ash in a deasphalting zone with at least aportion of residual oil derived from Hawkins crude and liquefied gaseoushydrocarbon to form a deasphalted oil having a substantially reduced ashcontent and desirable as a feed stock for catalytic cracking.

More specifically the present invention is directed to a procedurewhereby a residual petroleum fraction, that is a fraction containing amajor portion of components boiling above 900 F. and contaminated with asubstantial amount of ash including metal contaminants which have astheir origin metal contaminants present in, the crude oil as producedfrom the earth, is treated to secure a fraction having a low :ashcontent. The treating step is carried out by contacting in adeasphalting zone the residual oil, at least a portion of residual oilderived from Hawkins crude free from constituents boiling belowapproximately 650 F., and liquefied normally gaseous hydrocarbon to formin the deasphalting zone a deasphalted oil phase with a substantiallyreduced ash content and an asphalt phase containing a large part of theash of the feed stock and separately withdrawing said phases from saiddeasphalting zone. The resultant deasphalted oil phase with low ashcontent is a desirable feed stock for a catalytic cracking processwhereas the residual oil with metal contaminants, which is the chargestock for said deasphalting zone, is an undesirable feed stock for acatalytic cracking process.

The residual oil derived from a crude petroleum from the Hawkins fieldin Texas may be described generally as an oil derived from Hawkins fieldcrude free from components boiling below about 650 F. Characteristics ofHawkins residual oils suitable for use as the wash oil in a process ofthe present invention, are set out hereafter in Table I:

States Patent Patented May 21, I957 2 TABLE I Typical wash oilinspections The present invention will now be described in greaterdetail in conjunction with thedrawing in which Fig. 1 is in the form ofa diagrammatic flow sheet illustrating one procedure, for carrying outthe deasphalting step for removing metallic contaminants from theresidual charge stock; and,

Fig 2 is in the form of a diagrammatic; flow sheet illustrating anotherprocedure for deasphalting the residual feed stockfor removing metalliccontaminants therefrom.

Turning now specifically to the drawing and first to Fig. 1, thedeasphalting step. is carried out in vessel A. A residual. fractionhaving ash containing metallic contaminants derived from. a crude oil ischarged through inlet line 11 and in the line has admixed therewith aHawkins residual oil through inlet line 12 andliquefied normally gaseoushydrocarbon such as propane introduced through inlet line 13. Theadmixture of residual charge oil, Hawkins residual oil and propanepasses into settling vessel A where two phases are allowed to separateby gravity settling. From drum A a propane solution of oil with agreatly reduced ash content and particularly suitable as the chargestock for a catalytic cracking step is withdrawn through line 14. and anasphalt fraction containing ash constituents is withdrawn through outletline 15.

It will be understood that Fig. l is schematic only and that variousauxiliary equipment well known to a workman skilled in the art will beused for performing additional Well known steps in the process as, forexample, the recovery of propane from the fractions withdrawn throughoutlet lines 14 and 15 for further use in the system.

An alternative procedure for removing metallic contaminants from aresidual fraction of crude oil is shown in Fig. 2. In Fig. 2 an asphaltsettling drum B is provided. The residual charge stock having ashcontaining metallic contaminants derived from crude oil is charged tosettling drum B by way of inlet line 20, a fraction of Hawkins residualoil is introduced to drum B by way of inlet line 21 and a liquefiednormally gaseous hydrocarbon is introduced into drum B through inletline 22. In drum B a phase separation takes place with the phasesseparating under the influence of gravity. A propane solution of oilwith a greatly reduced ash content and suitable as the charge stock to acatalytic cracking process is withdrawn through outlet line 23 and anasphalt fraction containing ash contaminants is withdrawn through outletline 24. As explained in conjunction with Fig. 1, Fig. 2 is schematiconly and auxiliary equipment such as means for recovering the propanefrom the fractions withdrawn through outlet lines 23 and 24 will beprovided for recovering propane for further use in the systern.

The inspections of residua from the distillation of typical crude oilscharged to refinery operations are set out hereafter in Table II. InTable II, columns 1, 2, 3, and 4 show the characteristics respectivelyof residua derived from a mixture of Gulf Coast and West Texas crudes, aWest Texas crude, a Panhandle crude and a Lagunillas crude.

3 TABLE 11 Typical feed stock inspections The catalytic cracking offractions of petroleum oils is well known to the art. A description ofsuch a catalytic cracking process may be found in U. S. Patent2,587,554, issued February 26, 1952, in the name of John Weikart. Insuch catalytic cracking operations it has been found that if thecharging stock contains appreciable amounts of ash including metalcontaminants, such as three pounds of nickel per thousand barrels ofcharge stock, the catalytic cracking process is adversely afiected.Other metal components such as vanadium and iron are undesirable but areless troublesome than nickel; in general, on a weight basis it may beconsidered that vanadium is perhaps as troublesome as nickel and iron isperhaps /2 as troublesome as nickel.

In carrying out the deasphalting step in the present invention where aHawkins residual oil is introduced into the deasphalting zone to serveas a selective solvent for the ash including metal contaminants wherebythe ash is removed selectively from the residual charge stock, thesolvent used is a liquefied normally gaseous hydrocarbon. The use ofliquefied normally gaseous hydrocarbon for deasphalting is well known.As specific examples of materials which may be used may be mentionedethane, propane, propylene, butylene, butane and mixtures thereof.Because of pressure limitations in the operating equipment, it ispreferred to use butane, propane, propylene and butylenes or mixturesthereof with a desirable commercial mixture consisting of 30% butane and70% propane.

The amount of Hawkins residual to be employed will be at least about 5%by volume of the mixture of residua in the deasphalting zone. Excellentresults have been achieved with amounts in the range of 20% to about 50%Hawkins residual.

The preferred amount of solvent employed in the deasphalting step iswithin the range of about 2 to about volumes of solvent per volume ofHawkins residual oil charged to the deasphalting step. As a specificexample, 3 volumes of solvent per volume of residual oil charged is adesirable commercial ratio.

The temperature at which the deasphalting step is conducted may bewithin the range of about 100 to about 300 F. As a specific example, atemperature of about 150 F. is desirable. Pressures sufficient toprovide a liquid phase are employed.

In order to illustrate further the advantages of the present invention,the following example is given:

EXAMPLE A Hawkins residual oil consisting of 29% bottoms from a pipestill charging straight Hawkins crude is designated hereafter in TableIII as residuum A. A mixture designated hereafter in Table III asresiduum B was made up consisting of the following percentages.

20% Heavy Coastal Mixed Sweet 6% Tomball 15 Mixed Sweet-Light West TexasMixture 43 West Texas-Salt Flat Mixture Residuum A was separatelydeasphalted, residuum B was separately deasphalted and equal parts ofresidua A and B in admixture were deasphalted. These results are 4reported in columns 1, 2, and 3, respectively, in Table III. In column 4the results obtained by separately deasphalting oils A and B andcombining the deasphalted products are given:

TABLEIII Residuum A B A+B (Equal A-l-B Sep- Parts). arate. Type ofProcessing In Mixtures... Deasphalted Oil Yield, 32 71 52 52.

Vol. Percent. Deasphalted Oil Quality, 4.0 4.0 4.0 4.0.

Conradson Carbon, Wt. Percent. Ash, Lbs./1000Bbls 1.3 6.9 3.0 5.2.Nickel, Lbs/1000 Bbls- 0.7 0.3

1 A= Pure Hawkins resld; 29% bottoms from pipe still charging straightHawkins crude.

1 Too low to measure.

It will be noted from the example that by carrying out the deasphaltingstep of the residual oil in the presence of Hawkins residuum as aselective solvent for the ash that the deasphalted oil resulting has amuch lower ash content than is obtained when the residual oil isdeasphalted without having Hawkins residual present in the deasphaltingzone.

While specific examples have been given illustrating the practice of thepresent invention, it will be understood that these specific examplesare given by way of illustration only and not by Way of limitation.

' The invention claimed is:

1. A method for treating a petroleum fraction feed stock containing amajor portion of components boiling above 900 F. and contaminated by asubstantial amount of ash including metallic contaminants consisting ofcontacting said fraction in a deasphalting zone with at least a portionof a residual oil derived from Hawkins crude free from constituentsboiling below approximately 650 F. and with liquefied normally gaseoushydrocarbon under conditions to form in said deasphalting zone adeasphalted oil phase having a substantially reduced content of ash andmetallic contaminants and an asphalt phase containing a major portion ofash constituents introduced into said deasphalting zone and separatelywithdrawing said phases from said deasphalting zone.

2. A method in accordance with claim 1 in which the contaminatedpetroleum fraction is contacted with an amount in the range from about5% to about 50% by volume of the residual oil derived from Hawkinscrude.

3. A method in accordance with claim 1 in which the conditions include atemperature within the range of about to about 300 F., pressuressuflicient to provide a liquid phase and a ratio of liquefied normallygaseous hydrocarbon to Hawkins residual oil in the range from about 2 toabout 10 volumes to one volume.

4. A method in accordance with claim 1 in which the liquefied normallygaseous hydrocarbon is a mixture of propane and butane.

5. A method for treating an asphalt-containing petroleum fraction feedstock containing a major portion of components boiling above 900 F. andcontaminated by a substantial amount of metallic contaminants whichcomprises deasphalting said feed stock with a liquefied normally gaseoushydrocarbon in the presence of a resid ual fraction derived from aHawkins crude, said Hawkins residual crude fraction being substantiallyfree from constituents boiling below approximately 650 F.

6. A method for treating an asphalt-containing petroleum fraction feedstock containing a major portion of components boiling above 900 F. andcontaminated by a substantial amount of metallic contaminants whichcomprises admixing said feed stock with a residual fraction derived froma Hawkins crude and with a liquefied normally gaseous hydrocarbon,charging said mixture to a settling zone to obtain phase separation,withdrawing a lighter phase comprising a solution in said liquefiedhydrocarbon of a solvent oil having a substantially reduced content ofmetallic contaminants and separately withdrawing from said settling zonean asphalt phase containing a major portion of the metallic contaminantscharged to said settling zone, said Hawkins residual fraction beingsubstantially free from constituents boiling below approximately 650 F.

7. A method for treating an asphalt-containing petroleum fraction feedstock containing a major portion of components boiling above 900' F. andcontaminated by a substantial amount of metallic contaminants whichcomprises charging said feed stock, a liquefied normally gaseoushydrocarbon and a residual fraction derived from a Hawkins crude to asettling zone under conditions to form a lighter phase and a heavierphase, withdrawing a lighter phase comprising a solution in saidliquefied hydrocarbon of a solvent oil having a substantially reducedcontent of metallic contaminants and separately withdrawing from saidsettling zone an asphalt phase containing a major portion of themetallic contaminants charged to said settling zone, said Hawkinsresidual fraction being substantially free from constituents boilingbelow approximately 650 F.

References Cited in the file of this patent UNITED STATES PATENTS2,009,710 Goodwin July 30, 1935 2,041,276 Bray May 19, 1936 2,053,485Lindeke et a1. Sept. 8, 1936 2,727,853 Hennig Dec. 20, 1955 2,729,589Waghorne et al. Jan. 3, 1956

1. A METHOD FOR TREATING A PETROLEUM FRACTION FEED STOCK CONTAINING AMAJOR PORTION OF COMPONENTS BOILING ABOVE 900*F. AND CONTAMINATED BY ASUBSTANTIAL AMOUNT OF ASH INCLUDING METALLIC CONTAMINANTS CONSISTING OFCONTACTING SAID FRACTION IN A DEASPHALTING ZONE WITH AT LEAST A PORTIONOF A RESIDUAL OIL DERIVED FROM HAWKINS CRUDE FREE FROM SONSTITUENTSBOILING BELOW APPROXIMATELY 650* F. AND WITH LIQUEFIED NORMALLY GASEOUSHYDROCARBON UN-